<?php

/**
 * Filter handler for taxonomy terms with depth.
 *
 * This handler is actually part of the node table and has some restrictions,
 * because it uses a subquery to find nodes with
 */
class views_handler_filter_term_node_tid_depth extends views_handler_filter_term_node_tid {

    function operator_options() {
        return array(
            'or' => t('Is one of'),
        );
    }

    function option_definition() {
        $options = parent::option_definition();

        $options['depth'] = array('default' => 0);

        return $options;
    }

    function extra_options_form(&$form, &$form_state) {
        parent::extra_options_form($form, $form_state);

        $form['depth'] = array(
            '#type' => 'weight',
            '#title' => t('Depth'),
            '#default_value' => $this->options['depth'],
            '#description' => t('The depth will match nodes tagged with terms in the hierarchy. For example, if you have the term "fruit" and a child term "apple", with a depth of 1 (or higher) then filtering for the term "fruit" will get nodes that are tagged with "apple" as well as "fruit". If negative, the reverse is true; searching for "apple" will also pick up nodes tagged with "fruit" if depth is -1 (or lower).'),
        );
    }

    function query() {
        // If no filter values are present, then do nothing.
        if (count($this->value) == 0) {
            return;
        } else if (count($this->value) == 1) {
            $placeholder = " = %d";
        } else {
            $placeholder = " IN (" . implode(', ', array_fill(0, sizeof($this->value), '%d')) . ")";
        }

        // The normal use of ensure_my_table() here breaks Views.
        // So instead we trick the filter into using the alias of the base table.
        // See http://drupal.org/node/271833
        // If a relationship is set, we must use the alias it provides.
        if (!empty($this->relationship)) {
            $this->table_alias = $this->relationship;
        }
        // If no relationship, then use the alias of the base table.
        else if (isset($this->query->table_queue[$this->query->base_table]['alias'])) {
            $this->table_alias = $this->query->table_queue[$this->query->base_table]['alias'];
        }
        // This should never happen, but if it does, we fail quietly.
        else {
            return;
        }

        // Now build the subqueries.
        $subquery = "\n  SELECT tn.vid FROM {term_node} tn\n";
        $where = "  WHERE tn.tid $placeholder\n";
        $args = $this->value;
        $last = "tn";

        if ($this->options['depth'] > 0) {
            $subquery .= "    LEFT JOIN {term_hierarchy} th ON th.tid = tn.tid\n";
            $last = "th";
            foreach (range(1, abs($this->options['depth'])) as $count) {
                $subquery .= "    LEFT JOIN {term_hierarchy} th$count ON $last.parent = th$count.tid\n";
                $where .= "    OR th$count.tid $placeholder\n";
                $args = array_merge($args, $this->value);
                $last = "th$count";
            }
        } else if ($this->options['depth'] < 0) {
            foreach (range(1, abs($this->options['depth'])) as $count) {
                $subquery .= "    LEFT JOIN {term_hierarchy} th$count ON $last.tid = th$count.parent\n";
                $where .= "    OR th$count.tid $placeholder\n";
                $args = array_merge($args, $this->value);
                $last = "th$count";
            }
        }

        $this->query->add_where(0, "$this->table_alias.$this->real_field IN ($subquery$where  )", $args);
    }

}
